WO2021209604A1 - Système de mesure fondé sur une fibre optique, procédé de mesure de paramètres et produit-programme informatique - Google Patents

Système de mesure fondé sur une fibre optique, procédé de mesure de paramètres et produit-programme informatique Download PDF

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WO2021209604A1
WO2021209604A1 PCT/EP2021/059917 EP2021059917W WO2021209604A1 WO 2021209604 A1 WO2021209604 A1 WO 2021209604A1 EP 2021059917 W EP2021059917 W EP 2021059917W WO 2021209604 A1 WO2021209604 A1 WO 2021209604A1
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Prior art keywords
optical fibre
measuring
measurement
mode
modes
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English (en)
Inventor
Krzysztof MARKIEWICZ
Jakub KACZOROWSKI
Lukasz SZOSTKIEWCZ
Alejandro Dominguez Lopez
Marek Napierala
Tomasz Nasilowski
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Inphotech Sp zoo
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Inphotech Sp zoo
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Priority to EP21723647.0A priority Critical patent/EP4115150B1/fr
Publication of WO2021209604A1 publication Critical patent/WO2021209604A1/fr
Priority to US17/967,316 priority patent/US12174049B2/en
Anticipated expiration legal-status Critical
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
    • G01D5/26—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
    • G01D5/32—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light
    • G01D5/34—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells
    • G01D5/353—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre
    • G01D5/35338—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre using other arrangements than interferometer arrangements
    • G01D5/35354—Sensor working in reflection
    • G01D5/35358—Sensor working in reflection using backscattering to detect the measured quantity
    • G01D5/35361—Sensor working in reflection using backscattering to detect the measured quantity using elastic backscattering to detect the measured quantity, e.g. using Rayleigh backscattering
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
    • G01D5/26—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
    • G01D5/32—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light
    • G01D5/34—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells
    • G01D5/353—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre
    • G01D5/35306—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre using an interferometer arrangement
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
    • G01D5/26—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
    • G01D5/32—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light
    • G01D5/34—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells
    • G01D5/353—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre
    • G01D5/35338—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre using other arrangements than interferometer arrangements
    • G01D5/35354—Sensor working in reflection

Definitions

  • optical fibre based measurement system Optical fibre based measurement system, method of measuring parameters, and computer program product
  • the object of the invention is to provide an optical fibre based measurement system, a method of measuring parameter, and a computer program product used for simultaneous measurement of at least one parameter representing a quantity, in particular those selected from the group of temperature, strain, radiation, and pressure.
  • optical fibres are mostly used for telecommunication applications, their modal properties also allow them to be used as sensing components of sensors. Typically, changes in the effective refractive index are directly measured and used to determine the appropriate measurand - temperature, pressure, radiation, or mechanical strain of the optical fibre by strain, stress, vibration, magnetic induction, or the type of surrounding medium.
  • Optical Frequency Domain Reflectometry is used to determine the effective refractive index as a function of optical fibre length by analysing signals reflected or scattered along the optical fibre - Ding, Zhenyang et al. "Distributed Optical Fiber Sensors Based on Optical Frequency Domain Reflectometry: A review.” Sensors (Basel, Switzerland) 18 (2016): 104 - 127.
  • the current state of the art includes numerous solutions for distributed parameter measurement using optical fibres based on signals that are scattered in the optical fibre.
  • Fresnel reflection occurs at the boundaries of layers, which can also provide useful signals.
  • An example of the utilization of Fresnel reflection is the use of optical fibres with Bragg grating.
  • Rayleigh scattering is the scattering of light under the influence of inhomogeneity of the medium in which light propagates.
  • One disadvantage of techniques involving the utilization of this phenomenon is the lack of direct information about temperature changes in the studied environment.
  • Raman effect is utilized to measure temperature using the Stokes and anti-Stokes signal intensity difference analysis in the optical fibre length function.
  • the light power analysis enables the determination of the absolute temperature, unfortunately with relatively small resolution - at the level of 1 m - in the optical fibre length function.
  • the utilization of Raman effect to monitor temperature requires using very sensitive detectors or a great amount of averaging as this effect is relatively weak.
  • modes propagating in multi-mode and multi-core optical fibres can be divided by: order (eigenfunction number), polarization understood as a point on a Poincare sphere, and the core number to which a given mode is related.
  • the fundamental LP01 mode is degenerated and consists of two perpendicularly polarised modes.
  • polarised modes In an optical fibre with perfect geometry, polarised modes have the same effective refractive index and the same cut-off wavelength. Actual optical fibres do not have a perfect geometry (e.g. due to fluctuations in refractive index distribution or external disturbances), which is why polarization modes do not propagate with the same velocity.
  • the measure of optical fibre birefringence is the difference in the effective refractive indices of polarization modes.
  • Optical fibres with a structure that forces the differentiation of effective refractive indices of polarization modes is called a polarization-maintaining optical fibre (e.g. PANDA or BOW-TIE optical fibres).
  • a polarization-maintaining optical fibre e.g. PANDA or BOW-TIE optical fibres.
  • each core can propagate LP01 modes with different polarization. If a multi-core optical fibre is also a multi-mode optical fibre, it means that the LP11 mode can propagate in at least one of its cores.
  • JP2009053159 there is disclosed an optical fibre device for measuring temperature of components of a motor vehicle equipped with a measuring optical fibre susceptible to Raman effect, i.e. the response of the optical fibre to excitation by light having a wavelength which is different from the excitation wavelength and dependent on temperature.
  • the measuring optical fibre according to JP2009053159 is laid next to vehicle's exergonic components.
  • Optical Frequency Domain Reflectometry has been applied in a device containing a tuneable laser and a detector connected by an optical path comprising polarization-maintaining optical fibres, polarization-maintaining couplers, including an interferometer consisting of a coupler equipped with an arm containing a reference optical fibre and an arm with a measuring optical fibre, which is a birefringent polarization-maintaining optical fibre with Bragg grating inscribed at measurement points.
  • the detector is a photodiode.
  • the device is equipped with a controller controlling the operation of the source via an analogue-to-digital converter, to which a detector is connected.
  • the system is equipped with an exciting element, introducing light into the system to two different polarization modes.
  • a disadvantage of the solution according to US2010141930A1 is the limited number of measurement points and the limited number of parameters that can be measured simultaneously. In some applications, not only strain and temperature have an impact on the propagation of measuring modes in the optical fibre, but also other environmental factors such as pressure and radiation.
  • the objective of the invention is to solve the problems identified in the state of the art and to provide a solution that enables measurement using the entire length of the measuring optical fibre, scalable to a greater number of parameters to be measured and adapted to operate with various environmental exposures.
  • the optical fibre based measurement system is equipped with a system for generating radiation with monotonically tuneable wavelength during sweep periods, an optical path and a detector connected to the system for generating radiation via the optical path.
  • the optical path contains an interferometer comprising a multi-port element and an attached measuring optical fibre sensitive to at least two environmental parameters, a mode excitation system adapted to excite in the measuring optical fibre at least a measuring mode with a first effective refractive index and a measuring mode with a second effective refractive index, having different sensitivity to these two parameters.
  • the measurement system contains a processing unit to which the detector is connected via an analogue-to-digital converter, and the processing unit is adapted to generate the control signal for the system for generating radiation.
  • the wavelength tuning range of the system for generating radiation is greater than or equal to 0.2 nm. Such a range provides sufficient resolution and measurement range for simple applications.
  • the wavelength tuning rate of the system for generating radiation is greater than 0.15 nm/s; it has been experimentally found that effective measurement of even relatively slowly variable parameters requires at least such a rate of sweeping; however, without the measurement of vibrations under the conditions of their occurrence, the measurement of the remaining parameters is burdened with unpredictable error. It is important that the wavelength of the radiation generated by the system for generating radiation to be tuned monotonically - then, even if the tuning is not linear, it can be corrected, and the measurement result can be assigned to a point in the measuring optical fibre.
  • the output optical power of the system for generating radiation is greater than or equal to 10 mW.
  • Working with such power range allows measurements to be made using measurement signals subject to Rayleigh scattering using available detectors.
  • the detector has a bandwidth of at least 400 kHz and Noise Equivalent Power of less than 10 pW-Hz -0.5 .
  • Noise Equivalent Power With a higher noise level, the error increases, which is unfavourably propagated numerically in the equation system which determines the measured parameters
  • the analogue-to-digital converter has at least 8 bits; lower number of bits leads to increase of quantization error, which unfavourably propagates numerically in the equation system which needs to be solved in order to determine the parameters under test.
  • the measuring optical fibre is adapted to guide modes with different effective refractive indices being sensitive to said parameters in different ways
  • the measuring optical fibre is provided e.g. terminated with an anti-reflection system ensuring reflection of less than or equal to -50 dB.
  • a higher level of reflection from the end of the measuring optical fibre hinders the processing of weaker measuring signals scattered along its length and results in errors that are subject to unfavourable numerical propagation when the parameter being determined is determined under conditions of variability of more than one parameter. Measuring under these conditions would require a structural modification of the measuring optical fibre, such as for example the application of a Bragg grating.
  • the multi-port element and the mode excitation system are enclosed in a separate housing.
  • This configuration not only allows to avoid failure or damage of these sensitive components when values of environmental parameters (vibrations, temperature) exceed the permissible range of operation of these sensitive components, but also allows the removal of an influence of said environmental parameters on the radiation generation system and detector and consequently improvement in the accuracy of a measurement, particularly when the correction of the non-linearity of tuning is applied with a use of an additional system.
  • Limited measurement range in measurements based on Optical Frequency Domain Reflectometry usually results not from the propagation loss of the optical fibre, but from the increase of the frequency of the measured signal together with the extension of the optical fibre. With high-resolution measurement systems, this may require electronic systems with large bandwidths up to the GHz range, which in effect are expensive or whose remaining parameters are worse. By separating the systems, it is possible to effectively reduce the frequency of the signal returning from a given location in the optical fibre. Such a solution allows placing the system components in stable environmental conditions without increasing the required system parameters. In addition, this solution reduces the length of the measuring optical fibre, which leads to a reduction of the occurring shot noise and consequently a higher signal-to-noise ratio.
  • the mode excitation system has a control input connected to the processing unit and is adapted to sequentially excite measuring modes in the measuring optical fibre.
  • the measuring optical fibre preferably has at least two cores and is equipped at the end with a fan-in/fan-out component and a loop connecting the two cores.
  • a fan-in/fan-out component and a loop connecting the two cores.
  • the system for generating radiation is connected to the optical path via the mode excitation system and the measurement system has a second detector. Both detectors are connected to optical path via polarization beam splitter.
  • the measurement optical fibre is birefringent and has fast axis and slow axis aligned with polarization axes of polarization beam splitter and the other elements of the optical path maintain polarization while mode excitation system is configured so that light fed to the optical path and measuring optical fibre has polarization slanted with respect to slow axis and fast axis.
  • the measurement system is equipped with a system for determining the non-linearity of tuning.
  • a system for determining the non-linearity of tuning makes it possible to compensate for the tuning non-linearity at the level of sample processing of recorded interference signals.
  • the multi-port element is preferably a circulator with isolation in the range from 40 dB to 86 dB. This results in a favourable ratio between the reference signal and the measurement signal, which translates into a reduction of measurement error.
  • the anti-reflection element preferably has a reflection coefficient lower than or equal to -60 dB, and even better, lower than or equal to -80 dB. This reduces error introduced by the signal reflected from the end of the measuring optical fibre.
  • a method of determining the parameter at the measurement point via an optical fibre based measurement system equipped with a measuring optical fibre which, by means of Optical Frequency Domain Reflectometry, records and analyses an interference signal, being a result of the interference of the measurement signal with the reference signal, according to the invention, is characterized in that the measurement system is used, according to the invention, and the measurement signal is obtained as a result of Rayleigh scattering in the structure of the measuring optical fibre.
  • the utilization of Rayleigh scattering allows measurement of parameter at any point of the measuring optical fibre.
  • the system for generating radiation cyclically sweeps, at a rate of at least 0.15 nm/s, the predefined range of wavelengths being at least 0.2 nm wide.
  • At least two measuring modes with different effective refractive indices and different sensitivity to environmental parameters, to which the measuring optical fibre is exposed, are excited in the measuring optical fibre.
  • measurement data is obtained allowing to formulate a system of equations from which more than one parameter to be measured can be determined in case in which more than one parameter is changed along the measuring optical fibre.
  • the interference signal is subjected to frequency filtration with at least one band-pass filter matched to the position of the measurement point along the measuring optical fibre.
  • a measure of similarity is determined as a function of shift in the wavelength domain of the interference signal frequency filtration result with the result of subjecting the calibration signal to the same filter, and on the basis of the wavelength value corresponding to the maximum of correlation, the change of effective refractive index is determined for each of the aforementioned measuring modes with different effective refractive indices, obtaining a system of equations from which the measured parameter is determined during the determination step.
  • System of equations can be solved so that only one parameter is determined or used to determine all variable parameters.
  • samples of the interference signal recorded using the detector and samples of the calibration signal are corrected with respect to the tuning non-linearity of the system for generating radiation.
  • At least three measuring modes with different effective refractive indices are preferably applied. This allows determining three parameters or reducing the error of determining fewer parameters. [0032] Preferably, more measuring modes is used than parameters is being determined. Such a solution makes it possible to formulate an overdetermined system of equations and reduce measurement error.
  • Measuring modes are preferably excited by subsequently selecting them by switching the mode excitation system with a signal from the processing unit. This solution enables measurements to be carried out with a single detector and allows the full use of the maximum length of the measuring optical fibre.
  • a multi-core measuring optical fibre is used with two cores connected by a loop, in which at least two measuring modes are excited simultaneously during one sweep. This means it is not necessary to switch measuring modes sequentially and still use one detector.
  • the maximum length of the measuring optical fibre is shortened because the measurement signal passed through the loop returns and travels the length of the measuring optical fibre again. Therefore, the optical path of the signal is a multiple of the length of the measuring optical fibre; using two cores and one loop, it is double the length.
  • the object of the invention is also a computer program product adapted to be stored in the memory of the processing unit, which is characterised by the fact that it contains instructions causing the execution of the method according to the invention.
  • the computer program preferably stores the calibration data - samples of the interference signal obtained under controlled measurement conditions.
  • Fig. 1a shows a block diagram of the device in the embodiment of the invention
  • Fig. 1b shows an example of multi-port element (imperfect circulator having ports C1, C2, C3) used in the interferometer in this embodiment of the invention
  • Fig. 1c shows alternative applicable multi- port element comprising two -20 dB couplers and circulator
  • Fig. 2 shows a schematic example of a multi-core measuring optical fibre
  • Fig. 3 depicts a flowchart for the embodiment of the method according to the invention
  • Fig. 4a shows a block diagram of the device in an alternative embodiment of the invention
  • Fig. 4b shows the interferometer measurement arm
  • FIG. 5 shows the flowchart for the method of measuring parameters using the device according to this alternative embodiment of the invention
  • Fig. 6 shows a block diagram of an embodiment with simple mode excitation system cooperating with birefringent measuring optical fibre
  • Fig. 7 presents a block diagram of the mode excitation system in the embodiment in which multiple measuring modes of different orders in multiple cores are excited.
  • the optical fibre based measurement system is equipped with a system for generating radiation Z with monotonically tuneable wavelength.
  • the system for generating radiation Z can be executed as a laser with wavelength ⁇ tuned with control signal s, particularly current-based, potentially equipped with an amplifier providing the required light power.
  • the ⁇ (s) dependence does not have to be linear, although it simplifies signal processing - it is enough that it is monotonical.
  • Lasers with an external resonant cavity provide a wavelength tuning range exceeding 0.2 nm and a tuning rate greater than 0.15 nm/s. They can also be combined with an amplifier providing an optical power of 10 mW. This solution is suitable for use as a source of radiation in the system for generating radiation Z according to the invention and enables measurements to be executed.
  • KOHERON PD100 photodiode system made of InGaAs gallium indium arsenide and a preamplifier with a 3.5 kV/W gain, 400kHz band and Noise Equivalent Power (NEP) of 10 pW ⁇ Hz -0.5 were used.
  • NEP Noise Equivalent Power
  • THORLABS FPD510-FC-NIR system comprised of a photodiode and preamplifier with 216 kV/W gain, 1 MHz bandwidth and NEP of less than 2 pW/sqrt(Hz), and even better by using an avalanche photodiode with an amplifier with 2160 kV/W gain, 100 MHz bandwidth and noise equivalent power of less than 0.5 pW/sqrt(Hz) - THORLABS APD410C.
  • the measuring optical fibre F is terminated with the anti-reflection element EA.
  • EA anti-reflection element
  • the anti-reflection element EA in this embodiment was obtained by splicing to the end of the measuring optical fibre F a section of optical fibre without a core - a 1 mm long glass cylinder. This section was then cleaved at an angle of 8° to obtain a reflection coefficient of -60 dB. If, additionally, the end of the measuring optical fibre prepared in this manner is immersed in an index matching liquid, which has a refractive index between the refractive index of glass and one, a -80 dB match is obtained.
  • the disadvantage of using a matching liquid is that the end of the measuring optical fibre F must be additionally protected.
  • the -60 dB match can be achieved by immersing the 8° cleaved end of the measuring optical fibre F in the index matching liquid even without an additional optical fibre section without a core.
  • the best results were achieved with a matching of -80 dB, completely satisfactory with -60 dB, but with a matching of -50 dB measurement can also be performed.
  • the control signal for the system for generating radiation Z is provided by the processing unit UP .
  • the detector D is connected to the processing unit UP via an 8-bit analogue-to-digital converter ADC with a bandwidth corresponding to that of the detector D or wider.
  • PICOSCOPE 2205A was used as the analogue-to-digital converter (ADC) . Higher calculation accuracy was achieved with the 12-bit PICOTECH 4224 converter. Further improvement was observed with the 16-bit PICOTECH 5243D converter.
  • the detector D is connected to the system for generating radiation Z via the optical path T .
  • the optical path T contains a system of components operating as the interferometer I , including the multi-port element EW, the mode excitation system P , and the connected thereto measuring optical fibre F which is sensitive to the environment and more specifically to variable physical quantities and parameters in the environment. In particular, these include temperature, pressure, strain, radiation.
  • the measuring optical fibre F is adapted to guide modes with different effective refractive indices, which are sensitive to individual parameters in different ways.
  • An example of such measuring optical fibre F is a PANDA type optical fibre, in which two different polarization modes can be guided.
  • the mode excitation system P controlled from the processing unit UP , adapted to sequentially excite in the measuring optical fibre F the first polarization mode during the first measurement and the second polarization mode during the second measurement. These modes have different effective refractive indices.
  • the mode excitation system P is implemented as a polarization rotator or polarization switch.
  • the light signal resulting from Rayleigh scattering in the measuring optical fibre F is recorded.
  • the intensity of the scattered signal depends on temperature and stress, as well as on the polarization mode subject to scattering. Due to the low intensity of Rayleigh scattering, the measuring optical fibre F must be terminated with the anti-reflection element EA providing a reflection of less than or equal to -50 dB. This results in a level of noise that is small enough to be able to formulate and solve SEQ a system of equations binding the parameters to be measured, on the basis of the effective refractive index values determined, despite the measurement error.
  • the operation of the interferometer I using multi-port element EW as shown in Fig. lb is based on the fact that the multi-port element EW is a non-perfect circulator enclosed with the mode excitation system P in a separate housing having a connector for the measuring optical fibre F and connectors for single-core and single-mode optical fibres OF1.
  • the circulator system with the measuring optical fibre F is the interferometer I, in which one arm is a measuring optical fibre F together with the anti-reflection element EA, and the other arm is an imperfectly isolated connection of the input port C1 and the output port C3 of the circulator.
  • the signal in the perfect circulator is isolated between the input port C1 and the output port C3.
  • the isolation is at a level of 50 dB.
  • the crosstalk signal is a reference signal in relation to the measurement signal returning from the measuring optical fibre F from the port C2.
  • the interferometer I configuration and a reference signal interfering with the measurement signal can also be obtained by using the multi-port element EW with a larger number of ports and, if required to provide reference signal, attaching to one of them a reference arm, i.e. a section of measuring optical fibre F terminated with the anti-reflection element EA attenuating the reflected signals by at least 40 dB.
  • a multi-port element EW can be realized not only as a circulator, but also another element with directional properties, e.g. a coupler or splitter or even a system of several such elements.
  • FIG. 1c An example using two 99 to 1 couplers C20a, C20b connected via optical fibre F31 and each having one arm connected to another and second arms connected via two of the three ports of circulator having the third port adapted for connecting with measuring optical fibre F is shown in Fig. 1c.
  • a first port W1 of the multi-port element EW is connected with a first port of the coupler C20a.
  • a second port of the coupler C20a is connected with a first port of the coupler C20b via optical fibre F31.
  • the coupler C20b has a second port connected to a third port W3 of the multi-port element EW.
  • a third port of the coupler C20a is connected with a first port of the circulator O via optical fibre F21.
  • a second port of the circulator O is connected with the third port of the coupler C20b. Remaining third port of the circulator O is connected to the second port W2 of the multi-port element EW, to which the measuring fibre F is connected.
  • the length of optical fibre F31 is shorter than sum of the lengths of the optical fibres F21 and F32 which is expressed as
  • Use of a single, imperfect circulator is simpler and gives lower risk of manufacturing errors, however using off-the-shelf couplers and circulator allows for better control over the parameters and reasonable repeatability by reducing inter-sample variability which contributes to better use of detector dynamics.
  • additional couplers can be used and a reference interferometer with more arms can be constructed. Such solutions are quite commonly used in OFDR techniques.
  • this housing can be connected by a long optical fibres OF1 to a separate housing containing the system for generating radiation Z , the detector D, and the processing unit UP.
  • these sensitive parts of the measuring device can be placed far away from the location where the quantity to be measured is to be tested. This ensures that they are not exposed to damage and only the interferometer I with the multi-port element EW, the mode excitation system P, and the measuring optical fibre F is located in the area subject to environmental exposure.
  • Such a solution is particularly advantageous in measurement tasks in which the measuring optical fibre F is exposed to changes of more than one parameter.
  • any of the variable parameters such as temperature, vibration, radiation, or magnetic field will change in the range exceeding beyond the normal operating conditions of sensitive components such as the laser of the system for generating radiation, the detector D, or the processing unit UP.
  • the systems for tuning non-linearity compensation of the tuneable radiation generators used in OFDR techniques are sensitive to mechanical vibrations and other parameters that can be measured - particularly temperature. Allowing the non-linearity compensation system to be exposed to the measured parameter causes the calibration signal and the interference signal to be compensated in different ways, which distorts the cross-correlation result.
  • the phenomena described lead to an increase in measurement error, which can be avoided by placing a separate housing with the interferometer I and the measuring optical fibre F in the location subject to environmental exposure.
  • optical fibre with two different polarization modes described above is to use as the measuring optical fibre F a multi-core optical fibre with at least two single-mode cores of different diameters and/or different doping.
  • the system is implemented in such a way that the mode with the first effective refractive index Mnl, constituting a first-order mode, is propagated in the first core 31, and the mode with the second effective refractive index Mn2, also constituting a first-order mode, is propagated in the second core 32.
  • the mode excitation system P is adapted to sequentially excite in the measuring optical fibre F the mode propagating in the first core 31 at the first measurement, and the mode propagating in the second core 32 at the second measurement.
  • the cores of the measuring optical fibre F have different profiles of the refractive index, the modes propagating in them differ in the effective refractive index and the sensitivity to the parameters to be measured.
  • the cross-section of a dual-core optical fibre meeting the aforementioned requirements is schematically shown in Fig. 2.
  • the first core 31 has a diameter of 4.5 pm and a numerical aperture of 0.1
  • the second core 32 has a diameter of 3 pm and a numerical aperture of 0.2.
  • the second core 32 is additionally surrounded by air holes 33, which reduces crosstalk between cores 31 and 32.
  • the air holes 33 have a diameter of 6 pm and the pitch defined as the distance between the centres of adjacent air holes 33 is 20 pm.
  • the coupling between the m-th core and the n-th core of a K-core measuring optical fibre F is expressed in decibels, absolute value of the scattering matrix coefficient Sm 1 n 2 of this measuring optical fibre F treated as a 2K-port multi-port component in which each end of each core is treated as a port.
  • ports m1 and m2 are connected by the m-th core and ports nl and n2 by the n-th core.
  • the mode excitation system P is implemented as an optical fibre switch and fan—in/fan—out component.
  • the anti-reflection element EA was obtained by splicing to the end of the measuring optical fibre F a section of optical fibre without a core - a 1 mm long glass cylinder. This section was then cleaved at an 8° angle and immersed in an index matching liquid, resulting in a matching level of -80 dB.
  • the anti-reflection element EA can be provided at the end of the measuring fibre, but also can take a form of an attenuator, separator or other device for supressing reflected signal, provided in the middle of the one long optical fibre. Naturally then only the part of said optical fibre would provide measurement signal and only this part can be considered measuring optical fibre. It is also possible to use very long measurement optical fibre and use only a segment of which and taking benefit of the fact that signal reflected from the remote end is attenuated by normal propagation attenuation.
  • the measuring optical fibre F can also be realized as a multi-mode optical fibre in which at least one higher-order mode is excited.
  • it could be a single-core optical fibre, in which the mode excitation system P excites the LP01 mode in the measuring optical fibre F during the first measurement, and the LP11 mode during the second measurement. These modes have different effective refractive indices.
  • the mode excitation system P is therefore implemented as a spatial phase modulator PMF or a series connection of an optical fibre optic-switch with a mode multiplexer.
  • a light signal is generated by means of the system for generating radiation Z tuned using a signal from the processing unit UP .
  • the result of the interference of the signal scattered (Rayleigh scattering) in the measuring optical fibre F with the reference signal is detected by the detector D . This is how the interference signal is obtained.
  • a correction of the tuning non-linearity of the system for generating radiation Z is carried out by the synchronization system (not shown in the figures).
  • this CM tuning non-linearity of the system for generating radiation Z is determined by means of an additional system (not shown in the figures).
  • the correction CC of interference signal samples recorded with the detector D takes place, so as to compensate for the designated non-linearity of tuning.
  • the band-pass filter used is centred at a given position in the measuring optical fibre F and its bandwidth corresponds to the required measurement resolution. For example, for a measurement resolution of 10 cm and a source tuning rate of 0.15 nm/s, the filter width is 20 Hz.
  • the signal resulting from the band-pass filtration FF of the interference signal during measurement using the j-th mode is compared to the calibration signal obtained for the same mode, subjected to the same filtration. The comparison is made at the step of correlation analysis XC by determining the cross-correlation between the interference signal and the calibration signal and shift of the maximum of this cross-correlation in relation to zero. The cross-correlation is determined separately for the subsequent selected modes.
  • the pattern takes the following general form: where:
  • XC j ( ⁇ ) is the cross-correlation for the j-th mode
  • S Mj ( ⁇ ) is the interference signal determined during the measurement using the j-th mode
  • S cai.j ( ⁇ ) is the calibration signal determined for the j-th mode; ⁇ is the wavelength;
  • ⁇ is the shift in wavelength
  • J-parameters and J-modes having different effective refractive indices and reacting differently to environmental factors, which represent the parameters to be measured (for example: strain, pressure, temperature, radiation), the condition for solving the system is a non-zero determinant of the measurement matrix where is a change in the effective refractive index of the j-th mode under the influence of the k-th physical quantity. While j ⁇ ⁇ 1...j ⁇ and k ⁇ ⁇ 1...j ⁇
  • the measurement matrix is not a square matrix.
  • the condition for the system's solvability is J ⁇ K and a non-zero determinant of the matrix that is the product of the measurement matrix and its transposition where is a change in the effective refractive index of the j-th mode under the influence of the k-th physical quantity, while j ⁇ ⁇ 1.../ ⁇ and k ⁇ 1...K ⁇ , and J>K.
  • the measure of the quality of a measuring optical fibre F is the value of the determinant of matrix where element is a change of the effective refractive index of the j-th mode under the influence of the k-th parameter. Maximizing the determinant of the presented matrix minimises the error of distinguishing individual parameters, resulting from the numerical propagation of the measurement error of determining the change in the effective refractive index of individual modes.
  • measuring optical fibre F is subjected to exposition on changes of two environmental factor affecting propagation of light and measured with two parameters use of two modes is enough to determine any of these parameters or both of them by solving entirely or partially the system of equations. It happens quite often that measuring optical fibre F is exposed to simultaneous changes of temperature and changes of strain while impact of other environmental factors and parameters on propagation of light is negligible.
  • birefringent measuring optical fibre F such as panda or bow-tie or elliptical-clad. and induce two different polarization modes therein.
  • An advantage of use of birefringent measuring optical fibre F is ease of generation of two modes simultaneously.
  • Mode excitation system P can therefore be realized as deliberately slanted splice in polarization maintaining system.
  • the best splicing angle is 45° degrees but angles within a range of 30° to 60° are still reasonable.
  • connection joint e.g., rotated splice can constitute the mode excitation system P as it provides an effect that both fast axis and slow axis modes are excited in the measuring optical fibre F .
  • Additional advantage of such configuration is that it is easy to speed up measurement by using additional detector D2.
  • Both detectors D and D2 are connected to optical path T via polarization beam splitter PBS aligned with slow axis and fast axis of the birefringent measuring optical fibre F .
  • An easy way to achieve that is to use slanted splicing between system for generating radiation Z and the optical path T as shown in Fig. 6.
  • mode excitation system P is very simple - it is just a connection - splice providing required angle between polarization of the light being fed and the slow and fast axes of the birefringent measuring fibre F .
  • the measuring optical fibre F and the mode excitation system P can be used where the measuring optical fibre F has two cores.
  • the first core 31 is designed to incorporate first- and second-order modes
  • the second core 32 is a birefringent single-mode core - two fundamental polarization modes can propagate in it.
  • Four modes with different effective refractive indices can propagate in such an optical fibre.
  • FIG. 7 The block diagram of the mode excitation system P working with this measuring optical fibre F is shown in Fig. 7.
  • This mode excitation system P consists of a combination of the optical switch PO, the spatial phase modulator PMF, the polarization switch PP, and the Fan—in/Fan—out component.
  • the first output of the optical switch PO is attached to the spatial phase modulator PMF, and the second output is attached to the polarization switch PP.
  • the spatial phase modulator PMF and the polarization switch PP are connected to the Fan—in/Fan—out component.
  • a control signal from the processing unit UP such a combination allows exciting the selected measurement mode from the four available modes in the measuring optical fibre F.
  • the mode excitation system P is a simple fan—in/fan—out component with one output connected to the multi-port element EW, while the second one is terminated by the anti-reflection element EA ensuring a reflection coefficient of less than or equal to -50 dB.
  • the anti-reflection element EA At the opposite end of the measuring optical fibre F, there is a fan—in/fan—out component whose outputs are connected to each other.
  • the result is the loop U which returns the signal coming from the first core 31 to the second core 32, which allows measuring the signal scattered in both cores of the measuring optical fibre F.
  • a good condition for the system of equations is easier to achieve by using the anti-reflection element EA matched to -80 dB.
  • the first mode with the first effective refractive index is propagated from the mode excitation system P to the loop U
  • the second measuring mode MN2 with the second refractive index is propagated from the loop U to the anti-reflection element EA.
  • a light signal is generated using the system for generating radiation Z tuned by a signal from the processing unit UP.
  • the result of the interference of the signal scattered (Rayleigh scattering) in the measuring optical fibre F with the reference signal is detected by the detector D.
  • Non-linearity correction enables correct identification of the exact point in the measuring optical fibre F where certain frequency components of the measurement signal, have been scattered to subsequently interfere with the reference signal at the detector D.
  • the reference signal is a result of the non-perfect isolation of the directional multi-port element EW.
  • this signal can be provided by using a coupler or splitter and the entire reference arm or even a more extensive section of the optical path T.
  • f i,j is the centre frequency of the filter designed to measure the i-th point on the j-th mode
  • L i is the distance of point P i for which the filter is determined from the multi-port element EW
  • Ltot means the total length of the measuring optical fibre F
  • n j is the effective group refractive index of the j-th measurement mode
  • s is the source tuning rate
  • ⁇ u is the optical length of the loop U
  • c is the speed of light in a vacuum.
  • Filter bands are selected as described above.
  • the number of measurement points being indexed is twice as high as the number of actual measurement points along the measuring optical fibre F . It is due to the fact that using two cores for measurement has that consequence that at each physical point in the measuring optical fibre F, the signal runs twice in single measurement - each time in a different core.
  • signals resulting from the band-pass filtration FF by filters selected for this point are compared to the calibration signal subjected to the same filtering.
  • the comparison is made at the step of correlation analysis XC by determining, as a function of wavelength, the measure of similarity of two signals represented in the frequency domain.
  • the first signal is the result of the filtration FF of the signal.
  • the second signal is the result of filtering with the same calibration signal filter.
  • the result of the comparison represents a change resulting from fluctuations in the parameters to be measured.
  • a good measure of similarity as a function of wavelength is the cross-correlation function.
  • the shift ⁇ i of its maximum in relation to zero is a measure of the deviation of parameters from the calibration conditions.
  • n e ff - is the effective refractive index under the calibration measurement conditions
  • ⁇ i is the shift of the cross-correlation maximum determined during measurements for point P i
  • ⁇ 0 is the central measurement wavelength.
  • the value n e ff is read from the tables for standard conditions (temperature, pressure, stress, radiation) under which the calibration measurement was performed. Alternatively, it is possible to determine this value using computer simulations.
  • Measurements made according to the method according to the invention are preceded by a calibration in which the measuring optical fibre F is placed in an environment with controlled parameters - e.g. in an environmental chamber.
  • a set of calibration signals is recorded, i.e. signals from the detector D obtained for all measurement modes.
  • it is sensible to update calibration signals to the current parameter values. In this way, a moving measurement range is achieved.
  • a disadvantage of this solution is the accumulation of error during the measurement.
  • the calibration signal is also subject to non-linearity correction.
  • the method according to the invention can be done automatically.
  • the processing unit UP is then a digital machine with memory that executes a computer program permanently or temporarily stored in that memory.
  • Industrial computers and FPGA systems work well.
  • Microcomputers or dedicated ASIC units can also be used.
  • [0101] The use of a multi-core optical fibre with cores connected at the end with a loop U as the measuring optical fibre F and the application of the method described above allows measuring the parameters with one sweep and the simultaneous measurement of more modes thanks to the fact that the measurement signal propagates repeatedly along the length of the measuring optical fibre F in different cores and thus in different modes. It is very convenient.
  • a disadvantage of such a solution is that the maximum length of the measuring optical fibre F allowing the measurement is shortened twice because the use of the loop U makes the optical path T of the measurement signal about twice as long as the physical length of the measuring optical fibre F.
  • any of the variable parameters such as temperature, vibration, radiation, or magnetic field will change beyond the normal operating conditions of sensitive components such as the laser of the system for generating radiation, the detector D, or the processing unit UP .
  • the systems for compensating for the tuning non-linearity of the tuneable radiation generators used in OFDR techniques are sensitive to mechanical vibrations and other parameters that can be measured - particularly temperature. Allowing the non-linearity compensation system to be exposed to the measured parameter causes the calibration signal and the interference signal to be compensated in different ways, which distorts the cross-correlation result.
  • the scope of the invention includes also hybrid solutions in which the measurement signal propagates along a measuring optical fibre F multiple times in one sweep, and thus the measurement is performed using more than one mode while simultaneously switching the mode excitation system P in subsequent sweeps, which measures subsequent modes - e.g., higher-order modes or polarization modes.
  • This allows the utilization of the advantages of both configurations of the devices according to the invention discussed above.
  • Those skilled in the art of OFDR techniques will easily apply detection solutions known in the state of the art, such as partial Fourier transforms, signal gating, or measuring dynamic changes, thus obtaining solutions within the scope of the invention defined by the attached claims.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Investigating Or Analysing Materials By Optical Means (AREA)
  • Instruments For Measurement Of Length By Optical Means (AREA)

Abstract

L'invention concerne un système de mesure fondé sur une fibre optique muni d'un système de génération de rayonnement (Z) présentant une longueur d'onde accordable de façon monotone pendant des périodes de balayage, un trajet optique (T) et un détecteur (D) connecté au système de génération de rayonnement (Z) par l'intermédiaire du trajet optique (T). Le trajet optique (T) comprend un interféromètre (I) comprenant un élément à ports multiples (EW) et une fibre optique de mesure fixée (F) sensible à au moins deux paramètres environnementaux, le système d'excitation de mode (P) adapté pour une excitation dans la fibre optique de mesure (F) au moins du mode de mesure (Mn1) présentant le premier indice de réfraction effectif et du mode de mesure (Mn2) présentant le second indice de réfraction effectif, présentant une sensibilité différente à ces deux paramètres. Le système de mesure comprend une unité de traitement (UP) à laquelle le détecteur (D) est connecté par l'intermédiaire d'un convertisseur analogique-numérique (CAN), et l'unité de traitement (UP) est conçue pour générer le signal de commande destiné au système de génération de rayonnement (Z). L'invention concerne également un procédé de mesure d'au moins deux paramètres et un produit-programme informatique.
PCT/EP2021/059917 2020-04-17 2021-04-16 Système de mesure fondé sur une fibre optique, procédé de mesure de paramètres et produit-programme informatique Ceased WO2021209604A1 (fr)

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116539189A (zh) * 2023-04-25 2023-08-04 广东电网有限责任公司 一种多芯光纤分布式传感系统及测量方法
US11971310B2 (en) * 2018-06-22 2024-04-30 Commissariat A L'energie Atomique Et Energies Alternatives Method for producing an optical fibre for a distributed measurement of temperature or deformation in a harsh environment using the Rayleigh backscattered signal
CN119164664A (zh) * 2024-09-18 2024-12-20 上海交通大学 一种基于荧光光纤的总温总压同步测量方法和系统
DE102024206322A1 (de) * 2024-07-04 2026-01-08 Volkswagen Aktiengesellschaft Photonisches Radarsystem mit simultaner Mehrpfadüberwachungseinrichtung

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116007662B (zh) * 2023-03-23 2023-06-20 中国船舶集团有限公司第七〇七研究所 一种光纤陀螺及光纤陀螺的角速度校正方法
CN116430432B (zh) * 2023-03-27 2024-12-06 山东大学 一种双芯复合材料光纤探头、制备方法，及基于该探头的双参量传感器
CN117433587B (zh) * 2023-12-14 2024-03-19 江苏南方通信科技有限公司 对称结构多参数弱光栅传感光缆、传感系统和测量方法

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2009053159A (ja) 2007-08-29 2009-03-12 Toyota Motor Corp 温度検出装置
US20100141930A1 (en) 2008-02-29 2010-06-10 Fujikura Ltd. Physical quantity measuring apparatus utilizing optical frequency domain reflectometry, and method for simultaneous measurement of temperature and strain using the apparatus
WO2014200986A1 (fr) * 2013-06-13 2014-12-18 Intuitive Surgical Operations, Inc. Fibre de détection à réseau de bragg sur fibre à pas variable et à chevauchement, et procédés et appareil pour une mesure de paramètre à l'aide cette dernière
WO2015088365A2 (fr) 2013-12-15 2015-06-18 Inphotech Sp. O. O. Fibre optique multicœur microstructurées (mmof), dispositif et procédé de fabrication d'un dispositif d'adressage indépendant des cœurs d'une fibre optique multicœur microstructurées
WO2015170355A1 (fr) * 2014-05-05 2015-11-12 Filippo Bastianini Appareil d'interrogation de capteurs répartis à fibre optique faisant appel à un interféromètre dans le domaine fréquentiel optique à diffusion brillouin stimulée

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7119325B2 (en) * 2003-01-27 2006-10-10 Bookham Technology Plc System and method for monitoring environmental effects using optical sensors
US7228017B2 (en) * 2005-09-30 2007-06-05 General Electric Company Fiber optic sensing device and method of making and operating the same

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2009053159A (ja) 2007-08-29 2009-03-12 Toyota Motor Corp 温度検出装置
US20100141930A1 (en) 2008-02-29 2010-06-10 Fujikura Ltd. Physical quantity measuring apparatus utilizing optical frequency domain reflectometry, and method for simultaneous measurement of temperature and strain using the apparatus
WO2014200986A1 (fr) * 2013-06-13 2014-12-18 Intuitive Surgical Operations, Inc. Fibre de détection à réseau de bragg sur fibre à pas variable et à chevauchement, et procédés et appareil pour une mesure de paramètre à l'aide cette dernière
WO2015088365A2 (fr) 2013-12-15 2015-06-18 Inphotech Sp. O. O. Fibre optique multicœur microstructurées (mmof), dispositif et procédé de fabrication d'un dispositif d'adressage indépendant des cœurs d'une fibre optique multicœur microstructurées
WO2015170355A1 (fr) * 2014-05-05 2015-11-12 Filippo Bastianini Appareil d'interrogation de capteurs répartis à fibre optique faisant appel à un interféromètre dans le domaine fréquentiel optique à diffusion brillouin stimulée

Non-Patent Citations (6)

* Cited by examiner, † Cited by third party
Title
AHN TAE-JUNG ET AL., SUPPRESSION OF NONLINEAR FREQUENCY SWEEP IN AN OPTICAL FREQUENCY-DOMAIN REFLECTOMETER BY USE OF HILBERT TRANSFORMATION
L. ZHANGL. D. COSTAZ. YANGM. A. SOTOM. GONZALEZ-HERRAEZL. THEVENAZ: "Analysis and Reduction of Large Errors in Rayleigh-Based Distributed Sensor", JOURNAL OF LIGHTWAVE TECHNOLOGY, vol. 37, no. 18, 15 September 2019 (2019-09-15), pages 4710 - 4719, XP011746170, DOI: 10.1109/JLT.2019.2917746
LUKASZ SZOSTKIEWICZMAREK NAPIERALAANNA ZIOLOWICZANNA PYTELTADEUSZ TENDERENDATOMASZ NASILOWSKI: "Cross talk analysis in multicore optical fibers by supermode theory", OPT. LETT., vol. 41, 2016, pages 3759 - 3762
YUKSEL ET AL., ANALYSIS AND SUPPRESSION OF NONLINEAR FREQUENCY MODULATION IN AN OPTICAL FREQUENCY-DOMAIN REFLECTOMETER
ZHENYANG ET AL.: "Distributed Optical Fiber Sensors Based on Optical Frequency Domain Reflectometry: A review", SENSORS (BASEL, SWITZERLAND, vol. 18, 2018, pages 104 - 127
ZHENYANG ET AL.: "Distributed Optical Fiber Sensors Based on Optical Frequency Domain Reflectometry: A review", SENSORS, vol. 18, 2018, pages 104 - 127

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11971310B2 (en) * 2018-06-22 2024-04-30 Commissariat A L'energie Atomique Et Energies Alternatives Method for producing an optical fibre for a distributed measurement of temperature or deformation in a harsh environment using the Rayleigh backscattered signal
CN116539189A (zh) * 2023-04-25 2023-08-04 广东电网有限责任公司 一种多芯光纤分布式传感系统及测量方法
DE102024206322A1 (de) * 2024-07-04 2026-01-08 Volkswagen Aktiengesellschaft Photonisches Radarsystem mit simultaner Mehrpfadüberwachungseinrichtung
WO2026008682A1 (fr) 2024-07-04 2026-01-08 Volkswagen Aktiengesellschaft Système radar photonique comprenant une unité de surveillance simultanée à trajets multiples
CN119164664A (zh) * 2024-09-18 2024-12-20 上海交通大学 一种基于荧光光纤的总温总压同步测量方法和系统

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